Hi Ravi,
Try to check this notes:
1846043 - Leasing documents: Runtime error SYSTEM_DATA_ALREADY_FREE
1596847 - Not allowed to access data that has already been released
1648539 - Runtime Errors: SYSTEM_DATA_ALREADY_FREE on End button
1494463 - Contract change triggers exception SYSTEM_DATA_ALREADY_FREE
1139210 - SYSTEM_DATA_ALREADY_FREE dump on Blind Transfer and End
1931946 - UTIL_SALES: SYSTEM_DATA_ALREADY_FREE upon assigning a PoD
However, tell us what are you doing to get this error.
Best regards.